The ability to do atmospheric sensing of the neutral atmosphere (troposphere and stratosphere) by space geodetic techniques has improved considerably over the last decade as a result of technological advances, larger regional and global ground-based networks, satellite-based missions and developments of appropriate models and algorithms.
Water vapour, the most abundant greenhouse gas, accounting for 60-70% of global warming, is under sampled in current operational meteorological and climate observing systems. Advancements in Numerical Weather Prediction (NWP) Models (higher resolution and hourly cycling update), to improve forecasting of extreme precipitation requires GNSS observations with better timeliness, as well as spatial and temporal resolution, than currently available.
The existence of more than 15 years of homogeneously reprocessed observations from permanent GNSS stations worldwide has high potential for monitoring trends and variability in atmospheric water vapour which will enable evaluation of systematic biases from a range of instrumentation, improve the knowledge of climatic trends of atmospheric water vapour and also be of benefit to global and regional NWP reanalyses and climate model simulations.
NWP data has recently been used for deriving improved mapping functions. In real-time GNSS processing there is currently an interest in using atmospheric NWP data to initialise Precise Point Positioning processing algorithms which can provide shorter convergence time and improve positioning.
We welcome, but not limit, contributions on the following subjects:
Physical modelling of the neutral atmosphere using ground-based and radio-occultation data.
Multi-GNSS tropospheric products: their accuracy, consistency and benefits against a stand-alone GPS product.
PPP GNSS processing exploiting the potential use of IGS real-time precise orbits and clock products.
Studies on how to mitigate atmospheric effects for improving GNSS positioning, navigation, and observations at radio wavelengths.
Usage of GNSS measurements in weather forecasting (e.g., NWP and now-casting) and the impact of it.
Use of GNSS data in climate monitoring.
Technique validation or inter-technique comparisons (e.g. against radiosondes, microwave radiometers, sun photometers, LIDAR, satellite water IWV products such as those from GOME-2, SCHIAMACHY, IASI, SSM/I, SSMI/S and radio occultation instruments) and inter-system calibration.
Assessment and discussion of neutral atmospheric effects on the GNSS signals and on other techniques at radio wavelengths, such as VLBI, DORIS, InSAR and spacecraft ranging, as well as current techniques to perform neutral atmosphere media calibration.